488 Miscellaneous Intelligence. 



upon cooling. These crystals were colourless and transparent, 

 inodorous, insipid, very slightly soluble in cold water, but very 

 soluble in hot water ; they were similarly affected by alcohol and 

 ether. Strong acids dissolved this substance, but it was not affected 

 by alkalies. It was formed of oxygen, hydrogen, and carbon, and 

 does not exist in oil of turpentine recently distilled. — Bull. Univ. 

 A. vii. 154. 



28. Preparation ofCafeine^ by M. Garot. — ^The coffee was broken 

 and then digested in boiling water ; the liquor obtained was brown, 

 and being treated with acetate of lead, yielded an abundant greenish 

 precipitate : this being removed by a filter, left a yellow liquor, 

 through which a current of sulphuretted hydrogen was passed to 

 separate a little lead remaining in it : the free acid left, was then 

 saturated by ammonia, and the clarified liquor, when evaporated, 

 gave crystals of cafeine.— Jo7zr de Phar. 



29. Black Dye and Ink prepared with Logwood. — The following is 

 a process for the preparation of a black dye, for which a patent was 

 taken out at Vienna, by Mr. Honig. Logwood is to be boiled 

 several times in water, and a little subcarbonate of potash to be 

 added to the decoctions, the quantity being so moderated that it 

 shall not change the colour to blue ; the stuff to be dyed is then to 

 be plunged into this bath. This stuff may be either animal or vege- 

 table. When it is well impregnated with colouring matter, it is to 

 be withdrawn, and, without being exposed to air, is to be introduced 

 into a solution of green vitriol, and left there until it has obtained 

 the desired black hue. In preparing the ink, the decoction of 

 logwood is used in place of the infusion of galls. 



30. Improvement in the Manufacture of Varnishes. — It is usual 

 in the manufacture of spirit varnishes, to mix glass or sand with 

 the resin, for the purpose of affording ready access of the alcohol to 

 all parts of the solid mass. M. Ferrari, however, recommends that 

 in place of these substances, a coarsely-powdered charcoal should 

 be used ; for the glass or sand frequently tends to aggregate the 

 resin at the bottom of the vessels, and protect it from the solvent, 

 whilst, on the contrary, the charcoal rather tends to raise and 

 divide it. The most advantageous proportion appears to be about 

 one ounce of charcoal to one pound of the spirit or the oil of 

 turpentine used. — Giornale de Fisica^ ix. p. 36. 



31. Substances obtained from Castor Oil, by MM. Bussy and 

 Lecanu. — These chemists have obtained three new fatty acids from 

 castor oil. One called ricinic acid, is fusible at 72°Fahr. ; another 

 termed elaiodic acid, is fluid below 32° Fahr. ; and the third, or Mar- 

 garitic acid, crystallizes in fine scales, and is not fusible below 264° 

 Fahr. These acids are volatile, more or less soluble in alcohol, and 



